Answer from cs61c-ah (Charles Lee 16102343) for Question 1
The preprocessor performs macro substitution, conditional compilation, and inclusion of named files. Lines beginning with #, perhaps preceded by white space communicate with this preprocessor. A token is any language token or a character sequence giving a file name as in the #include directive. It outputs and links together the result with other programs and libraries and connects eternal function and object references to their definitions. I think it would occur before the compiler.